This invention relates to a chemiluminescent detection apparatus and, more particularly, to a chemiluminescent detection apparatus which is capable of detecting and measuring the presence and concentration of ozone or other oxidant material in the upper atmosphere.
Because of efforts being undertaken to reduce atmospheric pollution, reliable methods are needed for monitoring the level of various individual noxious gases in the ambient atmosphere resulting from various effluent sources, such as vehicle exhausts, factory emissions and the like. The detection of the presence of pollutants in sub part per million levels by the observation of chemiluminescent reaction is particularly attractive because the method can be adapted to be continuous and because long path length observation is not required as in absorption spectroscopy. A chemiluminescent reaction occurs where a primary reactant, such as ozone, engages in a highly exothermic reaction with certain second reactants or reagents to emit radiant energy, usually in the infrared region. Sensitive detectors can be calibrated to respond to the chemiluminescent emission in direct proportion to the concentration of the primary or desired reactants in the sample being studied. Examples of such chemiluminescent detectors are taught in U.S. Pat. Nos. 3,271,113; 3,848,128; 3,984,688; 3,710,107 and 3,528,779.
Ozone in the upper atmosphere has been measured in the past by a rocket-borne ozonesonde which directly measures ozone concentration in a continuous manner, thereby yielding data showing the partial pressure of ozone as a function of altitude. However, these prior art ozonesondes relied on pressure differentials between the upper and the lower atmospheres to provide for a flow of the ozone over the detector and do not provide for a sampling of a large volume of air on a continuous basis.